i3 is one of the projects with a restrictive merge policy. Hence there are a couple of patches floating around, adding some functionality. Please enable epatch_user support for i3-ebuilds. Would make things a lot easier for users in Gentoo :)
+ 30 May 2013; Kacper Kowalik <xarthisius@gentoo.org> i3-4.5.1.ebuild: + Add epatch_user() wrt #471716 by René 'Necoro' Neumann <gentoo@necoro.eu>